According to his bio, Barnett was "responsible for the UK business, working with ISPs on the trial and deployment of Phorm's technology as well as overseeing our commercial relationships with advertisers, publishers and ad networks". But, with none of Phorm's initially-announced three interested UK ISPs having gone ahead with rollout and some publishers having become wary, there seems little prospect of UK success at this point.

Asked about Barnett's departure, whether he is being replaced, what it means for UK plans and whether there's any further reorganisation, Phorm declined to comment. It's not known whether Barnett is at a new job.

Phorm in June tried a new pitch, by offering users personalised content along with ads. But the focus has shifted to international – having secured a whiff of business through a trial by South Korea's KT, Phorm hired a local CEO there and has continued to say other international ISPs are interested, though none have been named for trial. A spokesperson tells paidContent:UK: "The trial with KT (Korea Telecom) is ongoing. We'll update the market (AIM) in due course."

Barnett joined after Phorm's big boardroom and executive clear-out in December 2008, which saw the exit of its UK CEO, CFO, COO and general counsel and four board members be replaced by a more London-based board. Barnett effectively replaced UK CEO Hugo Drayton, the former Telegraph new media director who became InSkin Media's CEO after the exit. At this point, the company has stopped listing its execs' names on its website.

There's nothing inherently wrong with ad targeting, of course (Google's doing quite well out of it) – but Phorm's method of profiling a user's every web visit via his/her ISP concerned digital liberties advocates and the clamour grew so loud that the European Commission ruled Britain was wrong to declare Phorm legal, ordering the country change its privacy laws as a result.

One thing's clear, though – institutional investors still see plenty of promise in Phorm. Lloyds Bank has continued to snap up Phorm shares despite the headlines. Related stories